Conformal theory of central surface density for galactic dark halos
Abstract
Numerous dark matter studies of galactic halo gravitation depend on models with a core radius of r0 and a central density of ρ0. The central surface density product ρ0r0 is found to be nearly a universal constant for a large range of galaxies. Standard variational field theory with Weyl conformal symmetry postulated for gravitation and the Higgs scalar field, without dark matter, implies nonclassical centripetal acceleration , for a = aN + , where Newtonian acceleration aN is due to observable baryonic matter. Neglecting a halo cutoff at a very large galactic radius, conformal is constant over the entire halo, and a = aN + is a universal function, consistent with a recent study of galaxies with independently measured mass, that constrains acceleration due to dark matter or to an alternative theory. An equivalent dark matter source would be a pure cusp distribution with a cutoff parameter determined by a halo boundary radius. This is shown to imply a universal central surface density for any dark matter core model.
References
[1] Kormendy J, Freeman KC. Scaling laws for dark matter haloes in late-type and dwarf spheroidal galaxies. Symposium - International Astronomical Union. 2004, 220: 377-397. doi: 10.1017/S0074180900183706
[2] Gentile G, Famaey B, Zhao H, et al. Universality of galactic surface densities within one dark halo scale-length. Nature. 2009, 461: 627.
[3] Donato F, Gentile G, Salucci P, et al. A constant dark matter halo surface density in galaxies. MNRA. 2018, 397: 1169.
[4] Mannheim PD. Alternatives to dark matter and dark energy. Prog. Part. Nucl. Phys. 2006, 56: 340.
[5] Mannheim PD, Kazanas D. Exact vacuum solution to conformal Weyl gravity and galactic rotation curves. ApJ. 1989, 342: 635.
[6] Mannheim PD, Kazanas D. Newtonian limit of conformal gravity and the lack of necessity of the second order Poisson equation. Gen. Rel. Grav. 1994, 26: 337.
[7] Mannheim PD. Some exact solutions to conformal Weyl gravity. Annals N.Y. Acad. Sci. 1991, 631: 194.
[8] Mannheim PD. Making the case for conformal gravity. Found. Phys. 2012, 42: 388.
[9] Nesbet RK. Cosmological implications of conformal field theory. Mod. Phys. Lett. A. 2011, 26: 893.
[10] Nesbet RK. Conformal gravity: dark matter and dark energy. Entropy. 2013, 15: 162.
[11] Nesbet RK. Dark energy density predicted and explained. Europhys. Lett. 2019, 125: 19001.
[12] Nesbet RK. Dark galactic halos without dark matter. Europhys. Lett. 2015, 109: 59001.
[13] Nesbet RK. Conformal theory of gravitation and cosmology. Europhys. Lett. 2020, 131: 10002.
[14] Nesbet RK. Conformal theory of gravitation and cosmic expansion. MDPI Symmetry. 2024, 16: 003.
[15] McGaugh SS, Lelli F, Schombert JM. The radial acceleration relation in rotationally supported galaxies. Phys. Rev. Lett. 2016, 117: 201101.
[16] Nesbet RK. Theoretical implications of the galactic radial acceleration relation of McGaugh, Lelli, and Schomber. MNRAS. 2018, 476: L69.
[17] Mohr PJ, Taylor BN, Newell DB. CODATA recommended values of the fundamental physical constants: 2010. Rev. Mod. Phys. 2012, 84: 1527.
[18] De Blok WJG. The core-cusp problem. Advances in Astronomy. 2010, 2010. doi: 10.1155/2010/789293
[19] Ou X, Eilers AC, Necib L, Frebel A. The dark matter profile of the Milky Way inferred from its circular velocity curve. MNRAS. 2024, 528: 693.
[20] Milgrom M. A modification of the Newtonian dynamics: Implications for galaxies. ApJ. 1983, 270: 371.
[21] Milgrom M. The central surface density of ‘dark halos’ predicted by MOND. MNRAS. 2009, 398: 1023.
[22] McGaugh SS. Milky Way mass models and MOND. ApJ. 2008, 683: 137.
[23] O’Brien JG and Moss RJ. Rotation curve for the Milky Way galaxy in conformal gravity. J. Phys. Conf. 2015, 615: 012002.
Copyright (c) 2024 R. K. Nesbet
![Creative Commons License](http://i.creativecommons.org/l/by/4.0/88x31.png)
This work is licensed under a Creative Commons Attribution 4.0 International License.